Abstract: Vertical transmission of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV)is believed to be a common feature in field populations of S. exigua. To assess whether genderaffects trans-generational virus transmission, four mating groups were performed using healthyand sublethally infected insects: i) healthy males (H♂) × healthy females (H♀); ii) infected males(I♂) × healthy females (H♀); iii) healthy males (H♂) × infected females (I♀) and iv) infectedmales (I♂) × infected females (I♀). These adults and their offspring were analyzed by qPCR todetect SeMNPV infection. Both males and females were able to transmit the infection to the nextgeneration, although females infected a higher percentage of the offspring and female-mediatedtransmission was more consistent than that of males. Venereal transmission appeared to be half aseffective as maternally-mediated transmission, and the main route of transmission is likelytransovarial rather than transovum. The prevalence of the infection in the offspring did not varyaccording to gender, therefore both males and females can be infected by their parents in similarproportions. Incorporating vertically-transmitted genotypes in biological insecticides might havethe potential for reducing pest densities and extending periods between virus applications.